I just got wheels for my Commander from a Grand Cherokee, they fit nicely.
The standard wheels on my Commander were;
17" x 7,5, bolt pattern 5x127, offset 43,8.
I replaced them with the GC tyres, the only difference is the offset, which is 50,8.
In Switzerland that is still within the allowed tolerance, and I have to say that the 14mm of added width do make a difference. I like it actually better now, it's a little more stable than before, feels better. Really good on and offroad.
The tyres are Goodyear Wranglers, imho the best you can get for a Commander. Of course at winter you need something like Nokian Tyres, those guys know their stuff about winter.
But please note that there are many different tyre sizes for both Commander and GC, so you need to be careful. And also you should consider the tyre pressure sensors in your cost calculations.
When going gets tough - the Commander gets going.